Rechargeable batteries such as lithium ion and magnesium ion batteries have numerous commercial applications. Energy density is an important characteristic, and higher energy densities are desirable for a variety of applications.
A magnesium ion in a magnesium or magnesium ion battery carries two electrical charges, in contrast to the single charge of a lithium ion. Improved electrode materials would be useful in order to develop high energy density magnesium batteries.
The insertion and extraction of magnesium ions from the active material may affect the structural integrity of the active material. For example, the magnesiation reaction of Bi may result in a volume increase by 167%, which may result in cracking or structural damage of Mg3Bi2 alloys used as an active material in an anode. Such cracking of the Mg3Bi2 alloy may cause the isolation of Bi, increase the impedance and eventually decrease the capacity of the electrode. There is therefore a need in the art for an improved anode active material for a magnesium battery that has improved cycling and electrochemical performance.